Reducing nitrogen leaching in vegetable fields is of great significance for reducing non-point source pollution in vegetable growing area. The characteristics of nitrogen leaching in tomato and pepper greenhouse vegetable fields were studied by using organic manure substitution for chemical fertilizer and water saving. The treatments were set up:Chemical fertilizer(HF)treatment，organic manure substitution for chemical nitrogen fertilizer 40%(TDN)treatment，organic manure substitution for chemical nitrogen fertilizer 40% and water saving 30%(TDN+JS)treatment . The results showed that the average nitrate nitrogen concentration of all treatment solutions in different vegetable seasons was 70.4～202.4 mg/L in the two monitoring years. The average nitrate nitrogen leaching rates of HF，TDN and TDN+JS treatments were 130.9，116.2，97.2 kg/hm²，respectively. Compared with the HF treatment，the nitrate nitrogen leaching of TDN was slightly decreased by 11.4% on average. Compared with the HF treatment，TDN+JS treatment significantly reduced nitrate leaching by 25.9% on average. Nitrate leaching is the main part of nitrogen leaching，accounting for 69.1% to 73.1% of total nitrogen leaching，and soluble nitrogen accounting for 77.2% to 79.3% of total nitrogen leaching. The yield of tomato was 33.0 ～ 50.8 t/hm² and that of pepper was 17.6～19.8 t/hm² in two years，and there was no significant difference among different treatments. It is indicated that the combination of organic manure substitution for chemical fertilizer and appropriate water saving is a good way to reduce nitrogen leaching in greenhouse field.